The nodular cast iron poles in the existing technology are mostly made of common nodular cast iron which has the tensile strength of 420 MPa, the yield strength of 280 MPa and the elongation of 10%, so the poles are easily bent by ice and snow in case of extremely severe ice or snow weather to cause power outage. Moreover, the common nodular cast iron poles cannot reach required bearing capability until certain wall thickness is met, thus leading to increase of weight and cost of the common nodular cast iron.